Tag Archives: Shenzhen University

Biosynthetic melanin nanoparticles enabled by genetically engineered bacterium

A January 13, 2023 news item on phys.org announces research into genetically engineering bacteria so they produce melanin nanoparticles, i.e., biosynthetic melanin nanoparticles, Note: Links have been removed,

Photothermal therapy (PTT) has attracted considerable attention for the treatment of tumors because it is minimally invasive and has spatiotemporal selectivity.

Melanin is a kind of multifunctional pigment found widely in mammals, plants and microbes, with great prospects as a PTT agent for cancer treatment. Unfortunately, commercially available melanin is mainly obtained by chemical synthesis or extraction from sepia, which hinders its large-scale production and causes some potential safety hazards.

Recently, a research team led by Prof. Yan Fei from the Shenzhen Institute of Advanced Technology (SIAT) of the Chinese Academy of Sciences, together with Prof. Lin Jing from Shenzhen University and Prof. Xu Xiaohong from Guangdong Medical University, heterologously expressed a tyrosinase gene in Escherichia coli to synthesize melanin nanoparticles under mild and environmentally friendly conditions.

Caption: Schematic illustration of biosynthetic melanin nanoparticles for photoacoustic imaging-guided photothermal therapy. Credit: SIAT [Shenzhen Institute of Advanced Technology]

A January 13, 2023 Chinese Academy of Sciences press release (also on EurekAlert but published January 12, 2023), which originated the news item, provides a little more detail about the research,

The biosynthetic melanin nanoparticles exhibited excellent biocompatibility, good stability, and negligible toxicity. “They had strong absorption in the near-infrared region and higher photothermal conversion efficiency (48.9%) than chemically synthesized melanin-like polydopamine nanoparticles under an 808-nm laser irradiation,” said Prof. YAN.

The researchers further evaluated the photoacoustic imaging performance and antitumor efficacy of biosynthetic melanin nanoparticles. The results showed that the biosynthetic melanin nanoparticles had excellent photoacoustic imaging performance and could be used for photoacoustic imaging-guided photothermal therapy in vivo

“Our study provided an alternative approach to synthesize PTT agents with broad application potential in the diagnosis and treatment of cancer,” said Prof. YAN.

Here’s a link to and a citation for the paper,

Biosynthesis of Melanin Nanoparticles for Photoacoustic Imaging Guided Photothermal Therapy by Meijun Fu, Yuping Yang, Zhaomeng Zhang, Yaling He, Yuanyuan Wang, Chenxing Liu, Xiaohong Xu, Jing Lin, Fei Yan. Small DOI: https://doi.org/10.1002/smll.202205343 First published: 29 December 2022

This paper is behind a paywall.

Gas nanomedicine

This study comes from China and it offers an overview of the state-of-the-art of gas nanomedicine and a roadmap for future research. A May 6, 2020 news item on Nanowerk announces the study,

Cancer is deadly, but available cancer treatment methods are quite limited. The use of therapeutic gas molecules such as H2 [hydrogen gas], NO [nitrogen oxide], CO [carbon monoxide] and H2S [hydrogn sulfide] for cancer treatment is promising owing to their unique properties for selectively killing cancer cells and protecting normal cells from damage from other traditional therapies.

However, these gases and most of their prodrugs lack the abilities of active intratumoral accumulation and controlled gas release, causing limited therapeutic efficacy and potential side effects. The development of precision and intelligent gas delivery nanomedicines can maximize the profits of gas therapy by enhancing the bio-availability and bio-safety of therapeutic gases.

More and more gas-releasing nanomedicines are being developed by virtue of multifunctional nanoplatforms, making it ever-increasingly expectable to make breakthrough in cancer treatment. Even so, there are still many gaps between gas therapy and nanomedicines, needing to be filled.

In a new overview published in the Beijing-based National Science Review, scientists at Shenzhen University, China propose a series of engineering strategies of advanced gas-releasing nanomedicines for augmented cancer therapy from four aspects, 1) stimuli-responsive strategies for controlled gas release, 2) catalytic strategies for controlled gas release, 3) tumor-targeted gas delivery strategies, 4) multi-model combination strategies based on gas therapy.

A May 6, 2020 China Science Press news release on EurekAlert, which originated the news item, provides a little more detail about the overview and about a future application as an assistive therapy in diseases such as coronovirus pneumonia,

“This review systematically dissects the roles of carrier and gas prodrug within nanomedicine for stimuli-responsive gas release, catalytic gas generation routes, tumor-targeted gas delivery approaches and gas therapy-based combination methods, and also provides an insight into their engineering principles and working mechanisms, and correspondingly proposed a series of superior engineering strategies of nanomedicines for gas therapy of cancer to guide the future research.” Dr. Yingshuai Wang said “We believe this review could provide inspiration for constructing advanced gas-releasing nanomedicines.”

Moreover, they have also pointed out current issues and gaps in knowledge, and have envisaged current trends and future prospects of advanced nanomedicines for gas therapy of cancer in this review.

“There are many gaps intriguing me, such as high tissue penetration stimuli-responsive gas release, the local, endless and prodrug-free generation of gases by catalysis, and the super ability of assisting other almost all therapies.” Prof. Qianjun He adds “It is noticeable, in the recent fight of novel coronavirus pneumonia, hydrogen therapy is playing an vitally important role in assisting large numbers of patients to improve oxygen inhalation, relieve hypoxia, and scavenge inflammation. I hope our hydrogen-producing medicines would make bigger contribution to human being in the near future.”

This illustration accompanies the news release,

Caption: Illustration of strategies for engineering advanced nanomedicines for augmented gas therapy of cancer. Credit: ©Science China Press

Here’s a link to and a citation for the paper,

Strategies for engineering advanced nanomedicines for gas therapy of cancer by Yingshuai Wang, Tian Yang, Qianjun He. National Science Review, nwaa034, https://doi.org/10.1093/nsr/nwaa034 Published: 27 February 2020

This appears to be an open access paper in PDF only.

For anyone new to the term, a prodrug is (Note: Links have been removed),

A prodrug is a medication or compound that, after administration, is metabolized (i.e., converted within the body) into a pharmacologically active drug.[1][2] Inactive prodrugs are pharmacologically inactive medications that are metabolized into an active form within the body. Instead of administering a drug directly, a corresponding prodrug might be used instead to improve how a medicine is absorbed, distributed, metabolized, and excreted (ADME).[3][4]

You can find out more in the Prodrug Wikipedia entry.